QVBoxLayout vs Qlabel - resizing issue

[migel]

simple adding lable into QVBoxLayout layout does not resize label .

QLabel *label = new QLabel("test");
QVBoxLayout *layout = new QVBoxLayout;
QWidget *widget = new QWidget;
widget->setLayout(layout);
layout->addWidget(label);

QLabel *label = new QLabel("test");
QVBoxLayout *layout = new QVBoxLayout;
QWidget *widget = new QWidget;
widget->setLayout(layout);
layout->addWidget(label);

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But when I add QTabWidget it resizes just fine.

I have tried this scenario using Q Designer and works there.

I have tried changing different sizePolicy of the label and widget, no luck.

what I am doing wrong ??